Research to date has predominantly focused on survival outcomes for this demographic, leaving less known about physical function and quality of life, both of which are well-established priorities for older patients.
To address this knowledge gap, we conducted a multicentre, prospective observational cohort study in older adults (aged 65 or older) with mCRPC and compared various measures of their physical function and quality of life, pre- versus post-initiation of chemotherapy, abiraterone, enzalutamide, or radium-223. Specifically, we examined daily function (with the Older Adults Resource Study-Instrumental Activities of Living scale), grip strength (with a Jamar dynamometer), gait speed (with 4-meter walks), timed chair stands (with 5 Times Sit-To-Stand tests), quality of life (with the Functional Assessment of Cancer Therapy-General questionnaire), fatigue (with the Edmonton Symptom Assessment System [ESAS] subscale), pain (with the ESAS subscale), and mood (with the Patient Health Questionnaire-9). Patients completed follow up measurements every 3 weeks while on chemotherapy, every 4 weeks while on radium-223, and every 1-3 months while on abiraterone or enzalutamide.
A total of 198 men (71 starting chemotherapy, 37 starting abiraterone, 67 starting enzalutamide, and 23 starting radium-223) were enrolled. The treatment cohorts were similar in terms of mean age (75.1 years), race, education level, working status, medication count, and Eastern Cooperative Oncology Group performance status, but at baseline, the chemotherapy group was somewhat frailer, based on Vulnerable Elder Survey-13 and the Geriatric-8 scores.
Patients assigned to chemotherapy generally started with worse physical function and quality of life than those receiving other treatments, but all physical function and most quality of life outcomes remained stable over time, with only mood and functional well-being worsening in all treatment cohorts. For all patients, pain improved over time; this is an important finding, as pain is one of the most frequently reported symptoms among men with mCRPC.
These results must be interpreted with caution in the context of our study’s limitations. First, sample sizes for the treatment cohorts were modest and uneven, with the recruitment of fewer patients planning for radium-223. Second, mood was measured at the start and end of treatment (after six months for chemotherapy and radiation; after approximately eleven months for abiraterone and enzalutamide) while the remaining outcomes were measured every three to four weeks (for chemotherapy and radiation) or every three months (for abiraterone and enzalutamide) until end of treatment; accordingly, long-term trends in physical function and quality of life beyond one year remain unknown. Finally, attrition was not insignificant, ranging from 22% to 42% by the six-month mark; comparison between the main analysis and worst-case sensitivity analyses revealed differences that were most pronounced for the patients receiving radium-223, which comprised the smallest treatment cohort.
In summary, physical function and quality of life appear to remain stable among most older men receiving chemotherapy, radiation, and androgen-receptor targeted therapy. Our findings provide some initial reassurance to clinicians and their older patients considering treatment for mCRPC, but further work with a larger sample size and longer follow-up, while minimizing attrition, is needed to better understand how elder-relevant outcomes are affected over the course of treatment for mCRPC.
Written by: Valerie S. Kim,1 Henriette Breunis,2 & Shabbir M.H. Alibhai2-4
- Temerty Faculty of Medicine, University of Toronto, Toronto, Canada
- Department of Medicine, University Health Network, Toronto, Canada
- Department of Medicine, University of Toronto, Toronto, Canada
- Institute of Health Policy, Management, and Evaluation, University of Toronto, Toronto, Canada